Plaster & render calculator
Enter the wall area and coat thickness, pick the material — cement render, gypsum plaster or skim — and get kilograms, bags and mixing water.
Units
📐 You need
Estimates are for planning. Always confirm quantities with your supplier before ordering.
Frequently asked questions
How much plaster do I need per square meter?
Gypsum plaster runs about 1 kg per m² per mm of thickness, cement render about 1.6–1.8 kg, and skim coat about 1–1.2 kg. At a typical 12 mm coat, that's roughly 12 kg/m² for gypsum and 20 kg/m² for cement render.
How thick should plaster be?
Undercoat plaster and render are usually 10–15 mm per coat; skim finishing is 2–3 mm. Very uneven masonry may need two undercoats — never try to pull 30 mm in one pass.
How many bags of plaster per room?
A 25 kg bag of gypsum plaster covers roughly 2 m² at 12 mm, or 9–12 m² as a 2–3 mm skim. Enter your own bag size in the calculator — coverage scales directly.
How much water does plaster need?
Gypsum plasters take roughly 0.5–0.7 L per kg, cement render about 0.2 L per kg of dry mix. Always follow the bag — too much water weakens any plaster.
About this calculation
This calculator uses the dimensions, waste allowance and material sizes entered above. MaterialCalc is developed by Igors Beļavskis, a construction contractor in Latvia. Results are planning estimates; confirm product coverage, local rules and site conditions before ordering.
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